Abstract:
Immunological memory is found in diverse populations of a class of lymphocytes
called T cells, that are held at roughly constant numbers. Its composition
is in continuous flux as we encounter new pathogens and cells are lost. The mechanisms
which preserve the memory T cell population in the face of these uncertain
factors are largely unknown. We propose a mechanism for homeostasis, driven by
density-dependent cell death, that both fits experimental data and naturally preserves
the clonal composition of the T cell pool with fluctuating cell numbers. It
also provides clues as to the source of differences in diversity between T cell memory
subpopulations.